Arsenic oxidation by UV radiation combined with hydrogen peroxide

摘要

Arsenic is a widespread contaminant in the environment around the world. The most abundantnspecies of arsenic in groundwater are arsenite [As(III)] and arsenate [As(V)]. Several arsenicnremoval processes can reach good removal yields only if arsenic is present as As(V). For thisnreason it is often necessary to proceed with a preliminary oxidation of As(III) to As(V) prior to thenremoval technology. Several studies have focused on arsenic oxidation with conventionalnreagents and advanced oxidation processes. In the present study the arsenic oxidation wasnevaluated using hydrogen peroxide, UV radiation and their combination in distilled and in realngroundwater samples. Hydrogen peroxide and UV radiation alone are not effective at the arsenicnoxidation. Good arsenic oxidation yields can be reached in presence of hydrogen peroxidencombined with a high UV radiation dose (2,000mJ/cm2n). The quantum efficiencies for As(III)noxidation were calculated for both the UV photolysis and the UV/H2O2 processes.